Control device for applying balanced forces to a pair of servient mechanisms

ABSTRACT

A control device for applying balanced forces to a pair of servient mechanisms. The control device has a control shaft mounted for rotation and axial translation in a housing. A pair of force-transmitting devices in the form of a push-pull control cables operatively connect the control device to the corresponding servient mechanisms, which may be located remotely of the control device. The control device has a pair of throw members in the form of bellcranks rotatably mounted on the housing for applying compressive or tensile stresses to the core of each push-pull cable. The control device also has a pair of link arms. One end of each link arm is operatively connected to a corresponding bellcrank by a universal joint spaced radially of the control shaft. The opposite end of each link arm is operatively attached to a lever arm, also by universal joints, and the lever arm is affixed to the control shaft for movement therewith. This second pair of universal joints is preferably also spaced radially of the control shaft in order to preclude interference between the two link arms and the control shaft or the housing, particularly as the latter moves through its rotational range. In any event, the second pair of universal joints may not be located in a common plane with both the control shaft and the first pair of universal joints and at the same time be spaced at the same radial distance from the control shaft as the first pair of universal joints if all the objectives of the present invention are to be achieved.

United States Patent [72] [mentor Richard D. Houk Stow, Ohio [21 Appl. No. 40,320 [22] Filed May 25, 1970 [45] Patented Sept. I4, 1971 [73] Assigncc North American Rockwell Corporation Pittsburgh, Pa.

[54] CONTROL DEVICE FOR APPLYING BALANCED FORCES TO A PAIR OF SERVIENT MECHANISMS Primary Examiner-Milton Kaufman Attorneys.lohn R. Bronaugh, Floyd S. Levison and E. Dennis O'Connor ABSTRACT: A control device for applying balanced forces to a pair of servient mechanisms. The control device has a control shaft mounted for rotation and axial translation in a housing. A pair of force-transmitting devices in the form of a push-pull control cables operatively connect the control device to the corresponding servient mechanisms, which may be located remotely of the control device. The control device has a pair of throw members in the form of bellcranks rotatably mounted on the housing for applying compressive or tensile stresses to the core of each push-pull cable. The control device also has a pair of link arms. One end of each link arm is operatively connected to a corresponding bellcrank by a universal joint spaced radially of the control shaft. The opposite end of each link arm is operatively attached to a lever arm, also by universal joints, and the lever arm is affixed to the control shaft for movement therewith. This second pair of universal joints is preferably also spaced radially of the control shaft in order to preclude interference between the two link arms and the control shaft or the housing, particularly as the latter moves through its rotational range. In any event, the second pair of universal joints may not be located in a common plane with both the control shaft and the first pair of universal joints and at the same time be spaced at the same radial distance from the control shaft as the first pair of universal joints if all the objectives of the present invention are to be achieved.

PATENTED SEP] 4197! sum 1 OF 4 RICHARD 0. HOUK ATTORNEYS PATENTED SEP] 4 am 3,604,284

sum 2 or 4 INVIiNI ()R. RICHARD D. HOUK GPW'DW ATTORNEYS PATENTED SEPI 4|a1| 3.504284 sum u 0F 4 INVISN'I'UR. RICHARD D. HOUK BY 'I' 03M; PA WW ATTORNEYS CONTROL DEVICE FOR APPLYING BALANCED I FORCES TO A PAIR OF SERVIENT MECHANISMS BACKGROUND OF THE INVENTION Many off-the-road vehicles employ skid-steering. Track-laying vehicles in particular have long employed such steering, but it is as equally adaptable to any vehicle wherein rotation of one or more wheels about a substantially vertical axis is neither desired nor possible to effect steering and wherein power and/or braking can be independently provided to the track, wheels or the like, i.e., the drive means, on either side of the vehicle.

Basically, skid-steering operates by selectively braking the drive means on that side of the vehicle to which the turn is to be made while maintaining power to the drive means on the opposite side of the vehicle. In more advanced embodiments, skid-steering is effected by selectively declutching and sequentially braking the drive means on that side of the vehicle to which the turn is to be made while maintaining, or even applying, power to the drive means on the opposite side of the vehicle. Although any number of embodiments to effect sequential clutching and braking have been employed to effect skid-steering, they can, at least for the most part, be generally described as having individual clutch elements, one connected to the drive means on each side of the vehicle. These clutch elements are individually movable in one direction from a neutral position into contact with a power element that is operatively connected to the prime mover of the vehicle and in the opposite direction from neutral into contact with a braking element.

Selective movement of the clutch elements between their respective power and brake elements has long been accomplished by dual, stick controls, one for each clutch element. Although the dual-stick-type control has been used successfully in those applications where steering is effected solely by braking, where the clutch elements are movable in one direction to power the drive means and in another direction to brake the drive means considerable difficulty is encountered in coordinating the use of dual sticks.

It must also be appreciated that the necessity to coordinate controls can not be obviated by eliminating the application of a braking force to the drive means on that side of the vehicle to which the turn is to be made after it has been declutched because a free wheeling drive means has been found to have a tendency to continue along a straight course and thus resist skid-steering. Hence, the operator must, for the more sophisticated skid-steering arrangements, learn to balance the application of power to one drive means exactly against the application of a braking force to the opposite drive means in order to accomplish a smooth turn. The tactile sensitivity required to effect such a turn requires an inordinate amount of skill and experience. In fact, it requires an extremely delicate touch even for the most skilled, a difficult task over smooth terrain but well-nigh impossible over rough terrain.

SUMMARY OF THE INVENTION It is, therefore, a primary object of the present invention to provide a control device that will divide input forces applied thereto and balance their application to a pair of servient mechanisms.

It is another object of the present invention to provide a control device, as above, that has a control shaft to which the input forces are applied as translating and/or rotating forces and will equally divide and balance their application to servient mechanisms as either a pair of oppositely directed forces or a pair of forces acting in substantially the same direction.

It is yet another object of the present invention to provide a control device, as above, that is particularly adapted to the operation of even sophisticated skid-steering arrangements; the oppositely directed forces smoothly balancing the application of power to the drive means on one side of a vehicle in relation to the application of a braking force to the drive means on the other side of the vehicle while the similarly directed forces are balanced simultaneously to apply either power or braking force on opposite sides of the vehicle.

It is a further object of the present invention to provide a control device adapted for the operation of a skid-steering arrangement, as above, in which the operator may actuate a single steering wheel rather than be required to actuate dual sticks.-

It is a still further object of the present invention to provide a control device adapted for the operation of a skid-steering arrangement, as above, and with which steering is accomplished by naturally oriented manipulations of a steering wheel; a turn being effected by allowing the operator to rotate the steering wheel in the direction he wishes to turn the vehicle; similarly, by translating the steering wheel axially forwardly the vehicle will go forward and by translating the stee ring wheel axially rearwardly the vehicle will stop.

These and other objects of the present invention, as well as the advantages thereof over existing prior art forms, will become apparent from the following detailed description of the attached drawings and are accomplished by means hereinafter described and claimed.

In general, a control mechanism embodying the concept of the present invention has a control shaft mounted for both rotation and axial translation in a housing. A pair of forcetransmitting devices operatively connect the control mechanism to a pair of servient mechanisms that may be located remotely of the control device.

The control device has a throw member for actuating each force-transmitting device, the throw member being movably mounted on the housing. The control device also has a pair of link means. One end of each link means is operatively connected to the corresponding throw member by a first pair of individual universal joints spaced radially of the control shaft. The opposite end of each link means is operatively connected to the control shaft by a second pair of individual universal joints. Although the second pair of universal joints are preferably spaced radially of the control shaft, and housing, in order to preclude the link means from bindingly engaging the control shaft and/or the housing when the control shaft is moved through its normal range, the location of the second pair of universal joints may be rather freely selected. The only restriction on the selection of the location for the second pair of universal joints being that they may not be located in the same plane with the control shaft, and at the same time be an equal radial distance from the control shaft as the first pair of universal joints if all the objectives of the present invention are to be achieved. When both pair of universal joints are located in the same plane as the axis, control shaft 40, about which the lever arm 50 rotates and when both pair of universal joints are, at the same time, located at an equal radial distance from that axis, rotation of the lever arm 50 when either bellcrank remains relatively fixed will effect a translatory motion to the lever arm without imparting an attendant motion to the other bellcrank, as is required to balance the forces applied by the bellcrank to their corresponding servient mechanisms.

One preferred embodiment of the present invention is shown by way of example in the accompanying drawings and is described in detail without attempting to show all of the various forms and modifications in which the invention might be embodied; the invention being measured by the appended claims and not by the details of the specification.

DESCRIPTION OF THE DRAWINGS FIG. I is a side elevation of a control device embodying the concept of the present invention operatively connected, by a pair of push-pull control cables, to a pair of remote, servient mechanisms such as the dual output clutch-brake device depicted in top plan and 'used for effecting skid-steering;

FIG. 2 is an enlarged side elevation of the control device depicted in FIG. 1;

FIG. 3 is a top plan of the control device, partly broken away and partly in section, taken substantially on line 3-3 of FIG. 2;

FIG. 4 is a perspective view of the subject control device with the components oriented in what is designated the neutral position;

FIG. 5 is a view similar to FIG. 4i with the components being depicted as having been moved in response to pure translation of the steering wheel (not shown) from the neutral position of FIG. 4 so as to apply simultaneous actuation of the cores of the two push-pull cables in the same direction;

FIG. 6 is a view similar to FIGS. 4 and 5 with the components of the control device being depicted as having been moved in response to pure translation of the steering wheel (not shown) from the neutral position of FIG. 4 so as to apply simultaneous actuation of the two push-pull cable cores in a direction oppositely of that depicted in FIG. 5; and,

FIG. 7 is a view similar to FIGS. 4-6, but appearing on the same sheet of drawings as FIG. 1, with the components of the control device being depicted as having been moved in response to rotation and sequential compound rotation and translation of the steering wheel (not shown) from the neutral position of FIG. 4 so as to apply equal and opposite actuation of the two push-pull cable cores.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring more particularly to the drawings, a control device embodying the concept of the present invention is indicated generally by the numeral 10 and is depicted, in FIG. 1, as being operatively connected to actuate a pair of servient mechanisms in the form of the dual output clutch-brake device 11 by a pair of motion-transmitting devices 12A and 128, respectively.

In view of the fact that two motion-transmitting devices 12A and 1213 can be simultaneously actuated by selective movement of a single wheel 13, some duplication of elements is employed within the control 10.

Those elements will, for the most part, be described generally and designated with appropriate numerals, but when it becomes necessary for purposes of clarity to distinguish whether the element is acting directly in concert with motion transmitting device 12A or 128, the suffixes A and/or B will merely be added to the numerals used to designate the element generally.

It must be appreciated that in many environments in which the control device 10 has application the selection of the servient mechanism to be operated by a particular push-pull cable 12A or 128 may not be important. In other environments, however, a definite preference may exist. For example, in the environment where the control device is operatively connected to a clutch-brake device 11 having dual outlets R and L for the individual operation of the drive means on the right and left side of the vehicle, respectively, the selection should be made in order to achieve substantial conformity between the direction in which the wheel 13 is moved and the resulting direction in which the vehicle moves. As will become subsequently clear from that portion of the description relating to the operation of the subject control device to achieve a skid turn, it is desirable that the push-pull cables 12A and 12B be crossed between their connection to the control 10 and the clutch-brake device 11. That is, even though the push-pull cable 12A is connected to the right hand side of the control 10, as viewed by an operator grasping wheel 13, that push-pull cable should be connected to the output L of the clutch-brake device I l, and vice versa.

The motion transmitting devices 12 may each well be a push-pull control cable in which a core 14 slidably reciprocates with a casing I5 to transmit mechanical motion by the application of either t nsile or compressive forces to the core 14 when at least the ends of the casing 15 are held in a fixed position relative to the core.

The casing of each cable has an end fitting I6 affixed thereto. Each end fitting I6 is preferably provided with some interfitting means (not shown) by which it can be operatively engaged, as by the dimple 17 (FIG. 2) on clamp 18, for securing the casing 15 to the housing 20 of the control 10.

An extension tube 21 (FIGS. 1 and 2) may be mounted to swivel on end fitting 16, as by a socket arrangement not shown. The extension tube 21 slidably receives an end rod 22, one end of which is connected to the core 14 interiorly of the tube 21. The extension tube 21 is closely fitted around the end rod 22 in order to guide the end rod and also to prevent excessive deflection of that portion of the core 14 sliding therein, particularly when subjected to compressive loads.

The end rods 22A and 22B are secured to corresponding throw members in the form of bellcranks 23A and 238, as by individual clevis connectors 24.

As best shown in FIG. 3, the housing 20 comprises a pair of laterally spaced sideplates 25A and 258 each secured to a mounting block 28 (FIGS. 1 and 2) as by a plurality of mounting bolts 29 cooperating with the corresponding flanges 30A and 308 on the respective sideplates 25A and 253. The pushpull cable casing 15A is depicted as being secured to sideplate 25A, and casing 158 is secured to sideplate 258.

A support shaft 31 is secured transversely between the sideplates 25 with the opposed ends extending transversely therebeyond. The two bellcranks 23A and 23B are rotatably mounted on the exposed ends of the support shaft 31 for interconnection with the corresponding end rods 22A and 228, respectively, by the clevis connectors 24. A spacer sleeve 32 is received over the support shaft 31 between the sideplates 25A and 25B. Spacer sleeves 33A and 33B are also received over the support shaft 31 exteriorly of the housing 20 to space the bellcranks 23 and clevis connectors 24 at a convenient working distance clear of the housing 20. Nuts 34A and 34B retain the bellcranks rotatably mounted on support shaft 31.

Also secured between the sideplate 25A and 25B are a pair of longitudinally spaced bearing blocks 35 and 36 in which a control shaft 40 is mounted for both rotation and axial translation. A pair of longitudinally spaced stop collars 41 and 42 are fastened to the control shaft 40 for cooperative interengagement with the bearing blocks 35 and 36, respectively, to limit the range through which the control shaft 40 may be axially translated.

The control shaft 40 may also pass through a bore 43 in an instrument panel 44 to carry the control wheel 13 on the end thereof. As shown, a grommet 45 may well be interposed between the edge of the bore 43 through the instrument panel 44 and the control shaft 40 in order to provide a low friction support for the control shaft.

A lever arm in the form of a beam 50 is secured to the control shaft 40 and extends transversely thereof. A link rod 51A connects the lever arm 50, at a point spaced radially of the control shaft 40, to bellcrank 23A, and a second link rod 518 similarly connects the lever arm 50 to bellcrank 233. Each connector means 52 between the lever arm 50 and the corresponding link rod 51, as well as the connector means 53 between each link rod 51 and the corresponding bellcrank 23 is in the form of a universal joint. As shown, the connector means 52 may each comprise a clevis 54 secured to the lever arm 50 for rotation about a first axis and a swing block 55 secured to the clevis 54 for swinging movement about a second axis oriented transversely of the first axis. The first axis may be defined by the post portion 56 of clevis 54, and the second axis may be defined by the wristpin 58 that connects the swing block 55 to the clevis 54. One end of each link rod 51 is anchored in the corresponding swing block.

The opposite end of each link rod SI is fastened within a similar, second swing block 59 comprising an element of each connector means 53. Each connector means 53 also incorporates a clevis 60 secured to the corresponding bellcrank 23 for rotation about a first axis that is preferably parallel to the axis of the support shaft 31 on which the bellcranks are rotatably mounted. Each swing block 59 is secured to the corresponding clevis 60 for swinging movement about a second axis oriented transversely of the first axis. Here, too, the first axis may be defined by the post portion 61 of clevis 60, and the second axis may be defined by the wristpin 62 that connects the swing block 59 to the clevis 60.

The connector means 53 must be spaced radially of the control shaft 40 to effect the desired rotation of the bellcranks 23 in response to rotation and/or translation of the control shaft 40, which motions are hereinafter more fully described.

As best seen in FIG. 3, the link rods 51 in the preferred embodiment are oriented angularly with respect to the planes in which the individual bellcranks 23 rotate so that a thrust stabilizer is highly desirable to preclude binding of the bellcranks. In order to effect stabilization of the thrust loadings imparted laterally to the plane in which the bellcranks 23 rotate, the post portion 61 of each clevis 60 may extend through an arcuate guide slot 65 in the adjacent sideplate 25. A pair of spaced flanges 66 and 68 extend radially from the post portion 61 of each clevis 60 to engage the opposite faces 69 and 70, respectively, of the corresponding sideplate 25.

In order best to appreciate the novel concept embodied in the aforedescribed structure, an explanation of its operation as a steering control in the environment of a sophisticated dual-output clutch-brake device 11 shall now be presented.

Reverting to FIG. 4, the neutral position of the control device is depicted. When the components of the control device are so disposed the clutch-brake device 11 is in neutral so that not only is no power available from outputs L and R but also no braking power is applied thereto.

Should the operator wish simultaneously to engage the clutch mechanisms in the clutch-brake device associated with each output, as he would, for example, to move the vehicle in a straight course forward, he need only press forward on the wheel 13 to translate the control shaft 40 from the neutral position depicted in FIG. 4 to the simultaneous clutch-engaging position depicted in FIG. 5.

As the control shaft 40 slides axially forwardly within the bearing blocks 35 and 36, the lever arm 50 is carried therewith. The translating force applied by the operator to the wheel is applied from the lever arm 50 equally to the two bellcranks 23 by the link rods 51.

The linear translation of the control shaft 40 and lever arm 50 effects rotary motion of the bellcranks 23 in their corresponding planes, transversely of the plane through which the lever arm 50 is translated, by virtue of the link rods 51 which accommodate the two, distinct types of motion by the universal connectors 52 and 53.

With regard to the multiplanar motions involved it is quite important to note that that component of the resultant force transmitted through each link rod 51 and applied parallel to the plane in which the corresponding bellcrank 23 rotates effects rotation of that bellcrank; whereas, the force component applied transversely of that plane is stabilized by the interaction of the radial flange 66 on the post portion 61 of each clevis 60 with the face 69 on the corresponding sideplate 25 of housing 20. Furthermore, it is mandatory, in order that the multiplanar motion be achieved, that the lines of action of the resultant forces transmitted through the link rods 51 not be permitted to intersect the axis about which the bellcranks 23 rotate.

When the foregoing conditions are net, the forward translation of the control shaft 40 causes the two bellcranks 23 to rotate in unison. As will be observed by comparing the disposition of the elements in FIG. 5 with their disposition as depicted in FIG. 4, bellcrank 23A has rotated in a counterclockwise direction to apply a tensile force to the core 14 in push-pull cable 12A. The bellcrank 238 (not shown in FIGS. 4 or 5) will be similarly rotated to apply an equal tensile force to the core 14 of the push-pull cable 128. These simultaneous forces, when applied to the clutch-brake device 11 will engage the clutch mechanisms therein associated with the two outputs L and R so that the vehicle will move forwardly.

Should it be desired to stop the vehicle, the operator would first translate the control shaft 40 rearwardly from the position depicted in FIG. 5 to the position depicted in FIG. 4 in order to disengage the clutch mechanisms. Continued, rearward translation from the position depicted in FIG. 4 to the position depicted in FIG. 6 actuates the braking mechanisms. As will be observed by comparing the disposition of the elements in FIG. 6 with their disposition as depicted in FIG. 5, the bellcrank 23A has rotated in a clockwise direction to apply a compressive force to the core 14 in push-pull cable 12A, and the bellcrank 238 (not shown in FIG. 4-6) will be similarly rotated to apply an equal compressive force to the core 14 of the push-pull cable 128. These simultaneous forces, when applied to the clutch-brake device ll disengage the clutch associated with the two transmissions therein and then sequentially actuate the braking mechanism associated with each output. Here, too, the linear translation of the control shaft 40 and lever arm 50 effects rotary motion of the two bellcranks 23 in separate planes oriented transversely of the plane in which the lever arm 50 moves. When applying simultaneous compressive forces to the two push-pull cable cores 14, the load is applied from the lever arm 50 to the two bellcranks 23 by virtue of tensile stresses imparted to the link rods 51 by the lever arm 50. Here again, that component of the resultant force transmitted through each link rod 51 and applied parallel to the plane in which the corresponding bellcrank 23 rotates, effects rotation of the latter, whereas, the force component applied transversely of that plane is stabilized by the interaction of the radial flange 68 on the post portion 61 of each clevis 60 with the face 70 on corresponding sideplate 25 of housing 20.

Should the operator desire to effect a skid turn, he may, by a rotational manipulation of wheel 13, engage the clutch mechanism associated with one output of the dual clutchbrake device 11 and actuate the braking mechanism associated with the other output. In order to appreciate the manner in which the subject control applies balanced, oppositely directed forces to two, servient mechanisms, the description of a typical skid turn will begin with the components of the control device 10 disposed in the neutral position, as depicted in FIG. 4, (the disposition of the lever arm in the neutral position of the control device is represented by the centerline 50' in FIG. 7) and then sequentially describe their movement from that position to and beyond the chain line and full line dispositions depicted in FIG. 7.

As the operator turns the wheel in the direction he wishes the vehicle to move, the control shaft 40 and the lever arm 50 are rotated therewith. Assuming that the operator wishes to turn the vehicle, for example, to the right, the control shaft and lever arm would be rotated in a clockwise direction as viewed in FIGS. 4 and 7. This simple rotation of lever arm 50 will rotate bellcrank 23A to apply a tensile stress in core 14 of push-pull cable 12A to engage the clutch mechanism associated with the drive means on the left side of the vehicle (output L), and will, at the same time, rotate bellcrank 238 to apply a compressive stress in core 14 of push-pull cable 128 to engage the braking mechanism associated with the drive means on the right side of the vehicle (output R) and will continue until either the clutch mechanism or the braking mechanism first offers resistance against rotation of the control shaft 40 and lever arm 50. At that point the control shaft and lever arm (as represented by chain lines in FIG. 7) will not only rotate but will also translate axially in a compound motion until the resistance offered against their rotation by the two servient mechanisms equalizes.

For example, let it be assumed that the braking mechanism for the drive means on the right side of the vehicle, the direction to which the turn is to be made, first oflers resistance to rotation of the control shaft 40 and lever arm 50. As such, and because of the cable crossover previously described, the bellcrank 238 will tend to resist further rotation. Under this condition, the impartation of a further rotative force to the control shaft 40 and lever arm 50 will, by compound rotation and translation of the lever arm 50, nevertheless continue to rotate bellcrank 23A until the clutch mechanism for the drive means on the left side of the vehicle offers a resistance to the rotation of the control shaft and lever arm equal to that previously offered by the brake mechanism for the drive means on the right side of the vehicle.

Continued rotation of the bellcrank 23A during the time that bellcrank 23B remains stationary is accomplished by multiplanar motions of the link rods 51. Because the bellcrank 238 has met with greater resistance than bellcrank 23A, the bellcrank 238 will tend to resist motion and continued rotary motion of the lever arm 50 will pivot the link rod 513 about the connector 538 on the temporarily stationary bellcrank 233. This pivotal movement of link rod 513 about connector 538 will permit the connector 528 to move along a helical path so that the motion of lever arm 50 will be a compounding of rotational and translational motions necessary to maintain the connector 528 at a constant distance, the length of link arm 518, from connector 533. This compound motion moves the connector 52A through the same incremental rotational and translational distances as connector 528 is moved. The resulting motion of connector 52A is, in turn, imposed upon the connector 53A, through link rod 51A, as a rotational movement of the bellcrank 23A. if, as assumed, the bellcrank 23B first meets with resistance while the control shaft 40 and lever arm 50 are being rotated clockwise, as viewed in FIG. 7 those elements will thereupon translate axially inwardly, as depicted by movement of the lever arm 50 from a location designated by the chain line representation thereof in FIG. 7 to a location designated by the solid line representation thereof in FIG. 7.

In order to prevent interference between the link rods 51 and the housing 20, it is desirable to space the connectors 52A and 52B radially outwardly of the axis about which the lever arm 50 moves, i.e., control shaft 40, but in order that relative motion between the two bellcranks 23 can be achieved to accomplish the application of equalized forces it is mandatory that the connectors 53 be spaced radially of the axis defined by control shaft 40. It must be appreciated that should the four connectors 52A, 52B, 53A and 538 be radially spaced at equal distances from the control shaft 40, it is imperative that they not lie in a single plane which includes the axis about which the control shaft and lever arm rotate in order to assure that the desired balancing of the forces can be achieved.

Reverting to the description of the operation of the subject control device 10 when the wheel is rotated in a clockwise direction, had it been assumed that the clutch mechanism for the drive means on the left side of the vehicle would have first offered resistance to clockwise rotation of the control shaft 40 and lever arm 50, the compound motion of the control shaft and lever arm would have included an increment of translational movement directed axially outwardly, toward the operator, to accommodate the multiplanar motion of the link rod 51A secured to the then temporarily stationary bellcrank 23A. In the same fashion as explained above, the link rod 518 would continue to rotate bellcrank 233 until it met with resistance equal to that met by bellcrank 23A.

in either event, after the two bellcranks 23 meet with equal resistance the application of continued turning force to the wheel 13 will result in purely rotational movement of the lever arm 50 (beyond the position depicted by the solid line representation in FIG. 7) to effect simultaneous actuation of the cores 14 connected to the two bellcranks 23 in equal and opposite directions. Thus, so long as the servient mechanisms react with equal resistance, rotation of the control shaft 40 and lever arm 50 in the controi device 10 will apply balanced, oppositely direct-operating forces against the servient mechanisms and as soon as either servient mechanism displays a resistance greater than that met in the operation of the other servient mechanism, the control shaft 44) and lever arm 50 will translate to accommodate whatever angular displacement of 'one bellcrank with respect to the other that is necessary to equalize the resistances offered thereagainst and thus assure the application of continuous equal and opposite forces thereto.

Counterclockwise rotation of the wheel l3, and thereby the control shaft 40 and lever arm 50 will, in the exact opposite manner, effect a left turn of the vehicle.

At this stage in the explanation as to the operation of the subject control device, it should be appreciated that if, during translation of the control shaft 40 and lever arm 50 from the neutral position (FIG. 4) to either the simultaneous clutching position depicted in FIG. 5 or the simultaneous braking position depicted in FIG. 6, one or the other of the servient mechanisms would tend to engage before the other (as reflected by the resistance offered against rotation of the corresponding bellcrank), the control shaft 40 and lever arm 50 will, in that situation, rotate to apply whatever additional actuation is required of one bellcrank with respect to the other in order to balance the forces applied thereby against the servient mechanisms.

As such, a control device embodying the concept of the present invention will, when operatively connected to servient mechanisms, divide a single input force into a pair of balanced forces directed either in the same direction or, selectively, in opposite directions and will otherwise accomplish the objects of the invention.

What is claimed is:

l. A control device for applying balanced forces to a pair of servient mechanisms by a pair of force-transmitting means connected respectively therebetween comprising, a housing, a throw member for each force-transmitting means, each throw member being movably mounted on said housing, a control shaft mounted in said housing for rotation and axial translation, a pair of link means having opposed ends, one end of each link means connected to a corresponding throw member at a location spaced radially of said control shaft, the other end of each link means operatively connected to the control shaft.

2. A control device, as set forth in claim I, in which the operative connection of each link means to the control shaft is accomplished by first universal joints.

3. A control device, as set forth in claim 2, in which each throw member is in the form of a bellcrank rotatably mounted on said housing and in which second universal joints connect each link means to the corresponding bellcrank.

4. A control device, as set forth in claim 2, in which a lever arm is secured to said control shaft for mounting said first universal joints radially of said control shaft.

5. A controi device, as set forth in claim 4, in which said lever arm is disposed to mount said first universal joints on opposite sides of said control shaft.

6. A control device, as set forth in claim 5, in which said throw members are mounted on said housing to be disposed on opposite sides of said control shaft.

7. A control device, as set forth in claim 6, in which said throw members are each in the form of a bellcrank rotatably mounted on said housing and in which second universal joints connect each link means to the corresponding bellcrank.

8. A control device, as set forth in claim 1, in which the ends of said link means operatively connected to said control shaft are spaced a greater radial distance from said control shaft than the ends of said link means connected to said throw member and in which a thrust stabilization means is operatively connected between each said throw member and said housing.

9. A control device, as set forth in claim 8, in which a universal joint connects each said link means to the corresponding throw member, said stabilization means comprising, a post portion on each said universal joint, and flange means on said post portion for engaging said housing.

lit). A control device, as set forth in claim 9, in which said housing has plate means, a pair of slot means in said plate means, each said post portion passing through one of said slot means and said flange means engaging opposite sides of said plate means.

1]. A control device, as set forth in claim 10, in which each slot means is arcuate with respect to the axis about which the throw member is in the form ofa bellcrank mounted for rotabellcrank to which the post portion received therein is operation about an axis. lively cqnnected.

12. A control device, as set fo 'th in c lgi r l l ig vhjgl i sz a iji 

1. A control device for applying balanced forces to a pair of servient mechanisms by a pair of force-transmitting means connected respectively therebetween comprising, a housing, a throw member for each force-transmitting means, each throw member being movably mounted on said housing, a control shaft mounted in said housing for rotation and axial translation, a pair of link means having opposed ends, one end of each link means connected to a corresponding throw member at a location spaced radially of said control shaft, the other end of each link means operatively connected to the control shaft.
 2. A control device, as set forth in claim 1, in which the operative connection of each link means to the control shaft is accomplished by first universal joints.
 3. A control device, as set forth in claim 2, in which each throw member is in the form of a bellcrank rotatably mounted on said housing and in which second universal joints connect each link means to the corresponding bellcrank.
 4. A control device, as set forth in claim 2, in which a lever arm is secured to said control shaft for mounting said first universal joints radially of said control shaft.
 5. A control device, as set forth in claim 4, in which said lever arm is disposed to mount said first universal joints on opposite sides of said control shaft.
 6. A control device, as set forth in claim 5, in which said throw members are mounted on said housing to be disposed on opposite sides of said control shaft.
 7. A control device, as set forth in claim 6, in which said throw members are each in the form of a bellcrank rotatably mounted on said housing and in which second universal joints connect each link means to the corresponding bellcrank.
 8. A control device, as set forth in claim 1, in which the ends of said link means operatively connected to said control shaft are spaced a greater radial distance from said control shaft than the ends of said link means connected to said throw member and in which a thrust stabilization means is operatively connected between each said throw member and said housing.
 9. A control device, as set forth in claim 8, in which a universal joint connects each said link means to the corresponding throw member, said stabilization means comprising, a post portion on each said universal joint, and flange means on said post portion for engaging said housing.
 10. A control device, as set forth in claim 9, in which said housing has plate means, a pair of slot means in said plate means, each said post portion passing through one of said slot means and said flange means engaging opposite sides of said plate means.
 11. A control device, as set forth in claim 10, in which each throw member is in the form of a bellcrank mounted for rotation about an axis.
 12. A control device, as set forth in claim 11, in which said slot means is arcuate with respect to the axis about which the bellcrank to which the post portion received therein is operatively connected. 